1. Field of the Invention
The present invention relates to a technique related to an image recording apparatus comprising a cable suspension type ascent/descent mechanism ascending or descending by means of winding or unwinding a cable, and in particular to a technique for controlling an ascent/descent mechanism, the control being performed in the operation for bumping the transport mechanism of the image recording apparatus against a recording position.
2. Description of the Related Art
An image recording apparatus which comprises a cable suspension type ascent/descent mechanism and which is capable of moving the position of a transport mechanism when an image recording is not performed or a maintenance work is carried out is known.
Such an image recording apparatus employs a wire, which is an example of a cable, to suspend an ascent/descent table used for mounting a transport mechanism (noted as “elevator table” hereinafter), which is used for transporting a recording medium by means of a belt or belts. Further, the transport mechanism body is made to ascend and descend by winding and unwinding, respectively, a pulley that is connected to a wire and driven by a motor. Further, the control is such that the transport mechanism is made to ascend so as to lift a recording medium close to a recording head when a recording process is carried out, while the transport mechanism is made to descend when the recording process is riot performed.
Reference patent document 1 (i.e., Laid-Open Japanese Patent Application Publication No. H08-133495) has disclosed a sheet transportation apparatus with a cable suspension type ascent/descent mechanism and an ascending/descending method used for an image recording apparatus.
The image forming apparatus disclosed in patent document 1 comprises an ascent/descent wire 53 connected to an ascent/descent tray 52 as shown in FIG. 1, so that an ascent/descent motor (not shown in a drawing herein) winding or unwinding the ascent/descent wire 53 causes the ascent/descent tray 52 to ascend or descend.
A sheet face sensor 54 is provided for detecting the upper limit position of the ascent/descent tray 52 so that an ascent/descent control unit (not shown in a drawing herein) stops the not-shown ascent/descent motor so as to stop the ascent/descent tray 52 when the sheet face sensor 54 detects a recording medium 51 stacked on the ascent/descent tray 52. The present stop position is the upper limit position.
Further, patent document 1 has also disclosed an ascending operation suppression method that is applied when an ascending operation for the ascent/descent tray 52 runs out of control. The image forming apparatus according to patent document 1 is equipped with a stopper member 55 at a position further above the aforementioned upper limit position so as to cause the ascent/descent tray 52 to bump the stop member 55, thereby stopping the ascending operation.